/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: scan.c,v 1.121 2005/07/20 15:32:28 dedekind Exp $
 *
 */
#include <jffs2_kernel.h>
#include <jffs2_types.h>
#include <jffs2_slab.h>
#include <jffs2_mtd.h>
#include <jffs2_page.h>
#include <jffs2_crc32.h>
#include "jffs2_nodelist.h"

#define DEFAULT_EMPTY_SCAN_SIZE 1024


#define DIRTY_SPACE(x) do { \
		c->free_size -= x; c->dirty_size += x; \
		jeb->free_size -= x ; jeb->dirty_size += x; \
		}while(0)
#define USED_SPACE(x) do { \
		c->free_size -= x; c->used_size += x; \
		jeb->free_size -= x ; jeb->used_size += x; \
		}while(0)
#define UNCHECKED_SPACE(x) do { \
		c->free_size -= x; c->unchecked_size += x; \
		jeb->free_size -= x ; jeb->unchecked_size += x; \
		}while(0)


#define noisy_printk(noise, args...) do { \
	if (*(noise)) { \
		printk(KERN_NOTICE args); \
		 (*(noise))--; \
		 if (!(*(noise))) { \
			 printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
		 } \
	} \
} while(0)

static uint32_t pseudo_random;

static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
                                  unsigned char *buf, uint32_t buf_size);

/* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
 * Returning an error will abort the mount - bad checksums etc. should just mark the space
 * as dirty.
 */
static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
                                 struct jffs2_raw_inode *ri, uint32_t ofs);
static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
                                  struct jffs2_raw_dirent *rd, uint32_t ofs);

#define BLK_STATE_ALLFF		0
#define BLK_STATE_CLEAN		1
#define BLK_STATE_PARTDIRTY	2
#define BLK_STATE_CLEANMARKER	3
#define BLK_STATE_ALLDIRTY	4
#define BLK_STATE_BADBLOCK	5

static inline int min_free(struct jffs2_sb_info *c)
{
    uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
    if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
        return c->wbuf_pagesize;
#endif
    return min;

}

static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size)
{
    if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
        return sector_size;
    else
        return DEFAULT_EMPTY_SCAN_SIZE;
}

int jffs2_scan_medium(struct jffs2_sb_info *c)
{
    int i, ret;
    uint32_t empty_blocks = 0, bad_blocks = 0;
    unsigned char *flashbuf = NULL;
    uint32_t buf_size = 0;
#ifndef CONFIG_JFFS2_DIRECT
    size_t pointlen;

    if (c->mtd->point)
    {
        ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
        if (!ret && pointlen < c->mtd->size)
        {
            /* Don't muck about if it won't let us point to the whole flash */
            D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
            c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
            flashbuf = NULL;
        }
        if (ret)
            D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
    }
#endif
    if (!flashbuf)
    {
        /* For NAND it's quicker to read a whole eraseblock at a time,
           apparently */
        if (jffs2_cleanmarker_oob(c))
            buf_size = c->sector_size;
        else
            buf_size = PAGE_SIZE;

        /* Respect kmalloc limitations */
        if (buf_size > 128 * 1024)
            buf_size = 128 * 1024;

        D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
        flashbuf = (unsigned char *)kmalloc(buf_size, GFP_KERNEL);
        if (!flashbuf)
            return -ENOMEM;
    }

    for (i = 0; i < c->nr_blocks; i++)
    {
        struct jffs2_eraseblock *jeb = &c->blocks[i];

        ret = jffs2_scan_eraseblock(c, jeb, buf_size ? flashbuf : (flashbuf + jeb->offset), buf_size);

        if (ret < 0)
            goto out;

        jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

        /* Now decide which list to put it on */
        switch(ret)
        {
        case BLK_STATE_ALLFF:
            /*
             * Empty block.   Since we can't be sure it
             * was entirely erased, we just queue it for erase
             * again.  It will be marked as such when the erase
             * is complete.  Meanwhile we still count it as empty
             * for later checks.
             */
            empty_blocks++;
            list_add(&jeb->list, &c->erase_pending_list);
            c->nr_erasing_blocks++;
            break;

        case BLK_STATE_CLEANMARKER:
            /* Only a CLEANMARKER node is valid */
            if (!jeb->dirty_size)
            {
                /* It's actually free */
                list_add(&jeb->list, &c->free_list);
                c->nr_free_blocks++;
            }
            else
            {
                /* Dirt */
                D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
                list_add(&jeb->list, &c->erase_pending_list);
                c->nr_erasing_blocks++;
            }
            break;

        case BLK_STATE_CLEAN:
            /* Full (or almost full) of clean data. Clean list */
            list_add(&jeb->list, &c->clean_list);
            break;

        case BLK_STATE_PARTDIRTY:
            /* Some data, but not full. Dirty list. */
            /* We want to remember the block with most free space
               and stick it in the 'nextblock' position to start writing to it. */
            if (jeb->free_size > min_free(c) &&
                    (!c->nextblock || c->nextblock->free_size < jeb->free_size))
            {
                /* Better candidate for the next writes to go to */
                if (c->nextblock)
                {
                    c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
                    c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
                    c->free_size -= c->nextblock->free_size;
                    c->wasted_size -= c->nextblock->wasted_size;
                    c->nextblock->free_size = c->nextblock->wasted_size = 0;
                    if (VERYDIRTY(c, c->nextblock->dirty_size))
                    {
                        list_add(&c->nextblock->list, &c->very_dirty_list);
                    }
                    else
                    {
                        list_add(&c->nextblock->list, &c->dirty_list);
                    }
                }
                c->nextblock = jeb;
            }
            else
            {
                jeb->dirty_size += jeb->free_size + jeb->wasted_size;
                c->dirty_size += jeb->free_size + jeb->wasted_size;
                c->free_size -= jeb->free_size;
                c->wasted_size -= jeb->wasted_size;
                jeb->free_size = jeb->wasted_size = 0;
                if (VERYDIRTY(c, jeb->dirty_size))
                {
                    list_add(&jeb->list, &c->very_dirty_list);
                }
                else
                {
                    list_add(&jeb->list, &c->dirty_list);
                }
            }
            break;

        case BLK_STATE_ALLDIRTY:
            /* Nothing valid - not even a clean marker. Needs erasing. */
            /* For now we just put it on the erasing list. We'll start the erases later */
            D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
            list_add(&jeb->list, &c->erase_pending_list);
            c->nr_erasing_blocks++;
            break;

        case BLK_STATE_BADBLOCK:
            D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
            list_add(&jeb->list, &c->bad_list);
            c->bad_size += c->sector_size;
            c->free_size -= c->sector_size;
            bad_blocks++;
            break;
        default:
            printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
            BUG();
        }
    }

    /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
    if (c->nextblock && (c->nextblock->dirty_size))
    {
        c->nextblock->wasted_size += c->nextblock->dirty_size;
        c->wasted_size += c->nextblock->dirty_size;
        c->dirty_size -= c->nextblock->dirty_size;
        c->nextblock->dirty_size = 0;
    }
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
    if (!jffs2_can_mark_obsolete(c) && c->nextblock && (c->nextblock->free_size & (c->wbuf_pagesize - 1)))
    {
        /* If we're going to start writing into a block which already
           contains data, and the end of the data isn't page-aligned,
           skip a little and align it. */

        uint32_t skip = c->nextblock->free_size & (c->wbuf_pagesize - 1);

        D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
                  skip));
        c->nextblock->wasted_size += skip;
        c->wasted_size += skip;

        c->nextblock->free_size -= skip;
        c->free_size -= skip;
    }
#endif
    if (c->nr_erasing_blocks)
    {
        if ( !c->used_size && ((c->nr_free_blocks + empty_blocks + bad_blocks) != c->nr_blocks || bad_blocks == c->nr_blocks) )
        {
            printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
            printk(KERN_NOTICE "empty_blocks %ld, bad_blocks %ld, c->nr_blocks %ld\n", empty_blocks, bad_blocks, c->nr_blocks);
            ret = -EIO;
            goto out;
        }
        jffs2_erase_pending_trigger(c);
    }
    ret = 0;
out:
    if (buf_size)
        kfree(flashbuf);
#ifndef CONFIG_JFFS2_DIRECT
    else
        c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
#endif
    return ret;
}

static int jffs2_fill_scan_buf (struct jffs2_sb_info *c, unsigned char *buf,
                                uint32_t ofs, uint32_t len)
{
    int ret;
    size_t retlen;

    ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
    if (ret)
    {
        D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
        return ret;
    }
    if (retlen < len)
    {
        D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
        return -EIO;
    }
    D2(printk(KERN_DEBUG "Read 0x%x bytes from 0x%08x into buf\n", len, ofs));
    D2(printk(KERN_DEBUG "000: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
              buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7], buf[8], buf[9], buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]));
    return 0;
}

static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
                                  unsigned char *buf, uint32_t buf_size)
{
    struct jffs2_unknown_node *node;
    struct jffs2_unknown_node crcnode;
    uint32_t ofs, prevofs;
    uint32_t hdr_crc, buf_ofs, buf_len;
    int err;
    int noise = 0;
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
    int cleanmarkerfound = 0;
#endif

    ofs = jeb->offset;
    prevofs = jeb->offset - 1;

    D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));

#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
    if (jffs2_cleanmarker_oob(c))
    {
        int ret = jffs2_check_nand_cleanmarker(c, jeb);
        D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n", ret));
        /* Even if it's not found, we still scan to see
           if the block is empty. We use this information
           to decide whether to erase it or not. */
        switch (ret)
        {
        case 0:
            cleanmarkerfound = 1;
            break;
        case 1:
            break;
        case 2:
            return BLK_STATE_BADBLOCK;
        case 3:
            return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
        default:
            return ret;
        }
    }
#endif
    buf_ofs = jeb->offset;

    if (!buf_size)
    {
        buf_len = c->sector_size;
    }
    else
    {
        buf_len = EMPTY_SCAN_SIZE(c->sector_size);
        err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
        if (err)
            return err;
    }

    /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
    ofs = 0;

    /* Scan only 4KiB of 0xFF before declaring it's empty */
    while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
        ofs += 4;

    if (ofs == EMPTY_SCAN_SIZE(c->sector_size))
    {
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
        if (jffs2_cleanmarker_oob(c))
        {
            /* scan oob, take care of cleanmarker */
            int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
            D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n", ret));
            switch (ret)
            {
            case 0:
                return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
            case 1:
                return BLK_STATE_ALLDIRTY;
            default:
                return ret;
            }
        }
#endif
        D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
        if (c->cleanmarker_size == 0)
            return BLK_STATE_CLEANMARKER; /* don't bother with re-erase */
        else
            return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
    }
    if (ofs)
    {
        D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
                  jeb->offset + ofs));
        DIRTY_SPACE(ofs);
    }

    /* Now ofs is a complete physical flash offset as it always was... */
    ofs += jeb->offset;

    noise = 10;

scan_more:
    while(ofs < jeb->offset + c->sector_size)
    {

        jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

        cond_resched();

        if (ofs & 3)
        {
            printk(KERN_WARNING "Eep. ofs 0x%08lx not word-aligned!\n", ofs);
            ofs = PAD(ofs);
            continue;
        }
        if (ofs == prevofs)
        {
            printk(KERN_WARNING "ofs 0x%08lx has already been seen. Skipping\n", ofs);
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        prevofs = ofs;

        if (jeb->offset + c->sector_size < ofs + sizeof(*node))
        {
            D1(printk(KERN_DEBUG "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n", sizeof(struct jffs2_unknown_node),
                      jeb->offset, c->sector_size, ofs, sizeof(*node)));
            DIRTY_SPACE((jeb->offset + c->sector_size) - ofs);
            break;
        }

        if (buf_ofs + buf_len < ofs + sizeof(*node))
        {
            buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
            D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
                      sizeof(struct jffs2_unknown_node), buf_len, ofs));
            err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
            if (err)
                return err;
            buf_ofs = ofs;
        }

        node = (struct jffs2_unknown_node *)&buf[ofs - buf_ofs];

        if (*(uint32_t *)(&buf[ofs - buf_ofs]) == 0xffffffff)
        {
            uint32_t inbuf_ofs;
            uint32_t empty_start;

            empty_start = ofs;
            ofs += 4;

            D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
more_empty:
            inbuf_ofs = ofs - buf_ofs;
            while (inbuf_ofs < buf_len)
            {
                if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)
                {
                    printk(KERN_WARNING "Empty flash at 0x%08lx ends at 0x%08lx\n",
                           empty_start, ofs);
                    DIRTY_SPACE(ofs - empty_start);
                    goto scan_more;
                }

                inbuf_ofs += 4;
                ofs += 4;
            }
            /* Ran off end. */
            D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));

            /* If we're only checking the beginning of a block with a cleanmarker,
               bail now */
            if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
                    c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys)
            {
                D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
                return BLK_STATE_CLEANMARKER;
            }

            /* See how much more there is to read in this eraseblock... */
            buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
            if (!buf_len)
            {
                /* No more to read. Break out of main loop without marking
                   this range of empty space as dirty (because it's not) */
                D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
                          empty_start));
                break;
            }
            D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
            err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
            if (err)
                return err;
            buf_ofs = ofs;
            goto more_empty;
        }

        if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ)
        {
            printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08lx. Wrong endian filesystem?\n", ofs);
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK)
        {
            D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK)
        {
            printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08lx\n", ofs);
            printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK)
        {
            /* OK. We're out of possibilities. Whinge and move on */
            noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08lx: 0x%04x instead\n",
                         JFFS2_MAGIC_BITMASK, ofs,
                         je16_to_cpu(node->magic));
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        /* We seem to have a node of sorts. Check the CRC */
        crcnode.magic = node->magic;
        crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
        crcnode.totlen = node->totlen;
        hdr_crc = crc32(0, &crcnode, sizeof(crcnode) - 4);

        if (hdr_crc != je32_to_cpu(node->hdr_crc))
        {
            noisy_printk(&noise, "jffs2_scan_eraseblock(): Node at 0x%08lx {0x%04x, 0x%04x, 0x%08lx) has invalid CRC 0x%08lx (calculated 0x%08lx)\n",
                         ofs, je16_to_cpu(node->magic),
                         je16_to_cpu(node->nodetype),
                         je32_to_cpu(node->totlen),
                         je32_to_cpu(node->hdr_crc),
                         hdr_crc);
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }

        if (ofs + je32_to_cpu(node->totlen) >
                jeb->offset + c->sector_size)
        {
            /* Eep. Node goes over the end of the erase block. */
            printk(KERN_WARNING "Node at 0x%08lx with length 0x%08lx would run over the end of the erase block\n",
                   ofs, je32_to_cpu(node->totlen));
            printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }

        if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE))
        {
            /* Wheee. This is an obsoleted node */
            D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
            DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
            ofs += PAD(je32_to_cpu(node->totlen));
            continue;
        }

        switch(je16_to_cpu(node->nodetype))
        {
        case JFFS2_NODETYPE_INODE:
            if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode))
            {
                buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
                D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
                          sizeof(struct jffs2_raw_inode), buf_len, ofs));
                err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
                if (err)
                    return err;
                buf_ofs = ofs;
                node = (void *)buf;
            }
            err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs);
            if (err) return err;
            ofs += PAD(je32_to_cpu(node->totlen));
            break;

        case JFFS2_NODETYPE_DIRENT:
            if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen))
            {
                buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
                D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
                          je32_to_cpu(node->totlen), buf_len, ofs));
                err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
                if (err)
                    return err;
                buf_ofs = ofs;
                node = (void *)buf;
            }
            err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs);
            if (err) return err;
            ofs += PAD(je32_to_cpu(node->totlen));
            break;

        case JFFS2_NODETYPE_CLEANMARKER:
            D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
            if (je32_to_cpu(node->totlen) != c->cleanmarker_size)
            {
                printk(KERN_NOTICE "CLEANMARKER node found at 0x%08lx has totlen 0x%lx != normal 0x%lx\n",
                       ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
                DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
                ofs += PAD(sizeof(struct jffs2_unknown_node));
            }
            else if (jeb->first_node)
            {
                printk(KERN_NOTICE "CLEANMARKER node found at 0x%08lx, not first node in block (0x%08lx)\n", ofs, jeb->offset);
                DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
                ofs += PAD(sizeof(struct jffs2_unknown_node));
            }
            else
            {
                struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
                if (!marker_ref)
                {
                    printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
                    return -ENOMEM;
                }
                marker_ref->next_in_ino = NULL;
                marker_ref->next_phys = NULL;
                marker_ref->flash_offset = ofs | REF_NORMAL;
                marker_ref->__totlen = c->cleanmarker_size;
                jeb->first_node = jeb->last_node = marker_ref;

                USED_SPACE(PAD(c->cleanmarker_size));
                ofs += PAD(c->cleanmarker_size);
            }
            break;

        case JFFS2_NODETYPE_PADDING:
            DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
            ofs += PAD(je32_to_cpu(node->totlen));
            break;

        default:
            switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK)
            {
            case JFFS2_FEATURE_ROCOMPAT:
                printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08lx\n", je16_to_cpu(node->nodetype), ofs);
                c->flags |= JFFS2_SB_FLAG_RO;
                if (!(jffs2_is_readonly(c)))
                    return -EROFS;

#ifndef CONFIG_JFFS2_WRITABLE
                DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
                ofs += PAD(je32_to_cpu(node->totlen));
                break;
#endif

            case JFFS2_FEATURE_INCOMPAT:
                printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08lx\n", je16_to_cpu(node->nodetype), ofs);
                return -EINVAL;

            case JFFS2_FEATURE_RWCOMPAT_DELETE:
                D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
                DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
                ofs += PAD(je32_to_cpu(node->totlen));
                break;

            case JFFS2_FEATURE_RWCOMPAT_COPY:
                D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
                USED_SPACE(PAD(je32_to_cpu(node->totlen)));
                ofs += PAD(je32_to_cpu(node->totlen));
                break;
            }
        }
    }


    D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
              jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));

    /* mark_node_obsolete can add to wasted !! */
    if (jeb->wasted_size)
    {
        jeb->dirty_size += jeb->wasted_size;
        c->dirty_size += jeb->wasted_size;
        c->wasted_size -= jeb->wasted_size;
        jeb->wasted_size = 0;
    }

    if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
            && (!jeb->first_node || !jeb->first_node->next_phys) )
        return BLK_STATE_CLEANMARKER;

    /* move blocks with max 4 byte dirty space to cleanlist */
    else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size)))
    {
        c->dirty_size -= jeb->dirty_size;
        c->wasted_size += jeb->dirty_size;
        jeb->wasted_size += jeb->dirty_size;
        jeb->dirty_size = 0;
        return BLK_STATE_CLEAN;
    }
    else if (jeb->used_size || jeb->unchecked_size)
        return BLK_STATE_PARTDIRTY;
    else
        return BLK_STATE_ALLDIRTY;
}

static struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
{
    struct jffs2_inode_cache *ic;

    ic = jffs2_get_ino_cache(c, ino);
    if (ic)
        return ic;

    if (ino > c->highest_ino)
        c->highest_ino = ino;

    ic = jffs2_alloc_inode_cache();
    if (!ic)
    {
        printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
        return NULL;
    }
    memset(ic, 0, sizeof(*ic));

    ic->ino = ino;
    ic->nodes = (void *)ic;
    jffs2_add_ino_cache(c, ic);
    if (ino == 1)
        ic->nlink = 1;
    return ic;
}

static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
                                 struct jffs2_raw_inode *ri, uint32_t ofs)
{
    struct jffs2_raw_node_ref *raw;
    struct jffs2_inode_cache *ic;
    uint32_t ino = je32_to_cpu(ri->ino);

    D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));

    /* We do very little here now. Just check the ino# to which we should attribute
       this node; we can do all the CRC checking etc. later. There's a tradeoff here --
       we used to scan the flash once only, reading everything we want from it into
       memory, then building all our in-core data structures and freeing the extra
       information. Now we allow the first part of the mount to complete a lot quicker,
       but we have to go _back_ to the flash in order to finish the CRC checking, etc.
       Which means that the _full_ amount of time to get to proper write mode with GC
       operational may actually be _longer_ than before. Sucks to be me. */

    raw = jffs2_alloc_raw_node_ref();
    if (!raw)
    {
        printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
        return -ENOMEM;
    }

    ic = jffs2_get_ino_cache(c, ino);
    if (!ic)
    {
        /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
           first node we found for this inode. Do a CRC check to protect against the former
           case */
        uint32_t crc = crc32(0, ri, sizeof(*ri) - 8);

        if (crc != je32_to_cpu(ri->node_crc))
        {
            printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08lx: Read 0x%08lx, calculated 0x%08lx\n",
                   ofs, je32_to_cpu(ri->node_crc), crc);
            /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
            DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
            jffs2_free_raw_node_ref(raw);
            return 0;
        }
        ic = jffs2_scan_make_ino_cache(c, ino);
        if (!ic)
        {
            jffs2_free_raw_node_ref(raw);
            return -ENOMEM;
        }
    }

    /* Wheee. It worked */

    raw->flash_offset = ofs | REF_UNCHECKED;
    raw->__totlen = PAD(je32_to_cpu(ri->totlen));
    raw->next_phys = NULL;
    raw->next_in_ino = ic->nodes;

    ic->nodes = raw;
    if (!jeb->first_node)
        jeb->first_node = raw;
    if (jeb->last_node)
        jeb->last_node->next_phys = raw;
    jeb->last_node = raw;

    D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
              je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
              je32_to_cpu(ri->offset),
              je32_to_cpu(ri->offset) + je32_to_cpu(ri->dsize)));

    pseudo_random += je32_to_cpu(ri->version);

    UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
    return 0;
}

static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
                                  struct jffs2_raw_dirent *rd, uint32_t ofs)
{
    struct jffs2_raw_node_ref *raw;
    struct jffs2_full_dirent *fd;
    struct jffs2_inode_cache *ic;
    uint32_t crc;

    D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));

    /* We don't get here unless the node is still valid, so we don't have to
       mask in the ACCURATE bit any more. */
    crc = crc32(0, rd, sizeof(*rd) - 8);

    if (crc != je32_to_cpu(rd->node_crc))
    {
        printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08lx: Read 0x%08lx, calculated 0x%08lx\n",
               ofs, je32_to_cpu(rd->node_crc), crc);
        /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
        DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
        return 0;
    }

    pseudo_random += je32_to_cpu(rd->version);

    fd = jffs2_alloc_full_dirent(rd->nsize + 1);
    if (!fd)
    {
        return -ENOMEM;
    }
    memcpy(&fd->name, rd->name, rd->nsize);
    fd->name[rd->nsize] = 0;

    crc = crc32(0, fd->name, rd->nsize);
    if (crc != je32_to_cpu(rd->name_crc))
    {
        printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08lx: Read 0x%08lx, calculated 0x%08lx\n",
               ofs, je32_to_cpu(rd->name_crc), crc);
        D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
        jffs2_free_full_dirent(fd);
        /* FIXME: Why do we believe totlen? */
        /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
        DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
        return 0;
    }
    raw = jffs2_alloc_raw_node_ref();
    if (!raw)
    {
        jffs2_free_full_dirent(fd);
        printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
        return -ENOMEM;
    }
    ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
    if (!ic)
    {
        jffs2_free_full_dirent(fd);
        jffs2_free_raw_node_ref(raw);
        return -ENOMEM;
    }

    raw->__totlen = PAD(je32_to_cpu(rd->totlen));
    raw->flash_offset = ofs | REF_PRISTINE;
    raw->next_phys = NULL;
    raw->next_in_ino = ic->nodes;
    ic->nodes = raw;
    if (!jeb->first_node)
        jeb->first_node = raw;
    if (jeb->last_node)
        jeb->last_node->next_phys = raw;
    jeb->last_node = raw;

    fd->raw = raw;
    fd->next = NULL;
    fd->version = je32_to_cpu(rd->version);
    fd->ino = je32_to_cpu(rd->ino);
    fd->nhash = full_name_hash(fd->name, rd->nsize);
    fd->type = rd->type;
    USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
    jffs2_add_fd_to_list(c, fd, &ic->scan_dents);

    return 0;
}

static int count_list(struct list_head *l)
{
    uint32_t count = 0;
    struct list_head *tmp;

    list_for_each(tmp, l)
    {
        count++;
    }
    return count;
}

/* Note: This breaks if list_empty(head). I don't care. You
   might, if you copy this code and use it elsewhere :) */
static void rotate_list(struct list_head *head, uint32_t count)
{
    struct list_head *n = head->next;

    list_del(head);
    while(count--)
    {
        n = n->next;
    }
    list_add(head, n);
}

void jffs2_rotate_lists(struct jffs2_sb_info *c)
{
    uint32_t x;
    uint32_t rotateby;

    x = count_list(&c->clean_list);
    if (x)
    {
        rotateby = pseudo_random % x;
        D1(printk(KERN_DEBUG "Rotating clean_list by %d\n", rotateby));

        rotate_list((&c->clean_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of clean_list is at %08x\n",
                  list_entry(c->clean_list.next, struct jffs2_eraseblock, list)->offset));
    }
    else
    {
        D1(printk(KERN_DEBUG "Not rotating empty clean_list\n"));
    }

    x = count_list(&c->very_dirty_list);
    if (x)
    {
        rotateby = pseudo_random % x;
        D1(printk(KERN_DEBUG "Rotating very_dirty_list by %d\n", rotateby));

        rotate_list((&c->very_dirty_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of very_dirty_list is at %08x\n",
                  list_entry(c->very_dirty_list.next, struct jffs2_eraseblock, list)->offset));
    }
    else
    {
        D1(printk(KERN_DEBUG "Not rotating empty very_dirty_list\n"));
    }

    x = count_list(&c->dirty_list);
    if (x)
    {
        rotateby = pseudo_random % x;
        D1(printk(KERN_DEBUG "Rotating dirty_list by %d\n", rotateby));

        rotate_list((&c->dirty_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of dirty_list is at %08x\n",
                  list_entry(c->dirty_list.next, struct jffs2_eraseblock, list)->offset));
    }
    else
    {
        D1(printk(KERN_DEBUG "Not rotating empty dirty_list\n"));
    }

    x = count_list(&c->erasable_list);
    if (x)
    {
        rotateby = pseudo_random % x;
        D1(printk(KERN_DEBUG "Rotating erasable_list by %d\n", rotateby));

        rotate_list((&c->erasable_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of erasable_list is at %08x\n",
                  list_entry(c->erasable_list.next, struct jffs2_eraseblock, list)->offset));
    }
    else
    {
        D1(printk(KERN_DEBUG "Not rotating empty erasable_list\n"));
    }

    if (c->nr_erasing_blocks)
    {
        rotateby = pseudo_random % c->nr_erasing_blocks;
        D1(printk(KERN_DEBUG "Rotating erase_pending_list by %d\n", rotateby));

        rotate_list((&c->erase_pending_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of erase_pending_list is at %08x\n",
                  list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list)->offset));
    }
    else
    {
        D1(printk(KERN_DEBUG "Not rotating empty erase_pending_list\n"));
    }

    if (c->nr_free_blocks)
    {
        rotateby = pseudo_random % c->nr_free_blocks;
        D1(printk(KERN_DEBUG "Rotating free_list by %d\n", rotateby));

        rotate_list((&c->free_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of free_list is at %08x\n",
                  list_entry(c->free_list.next, struct jffs2_eraseblock, list)->offset));
    }
    else
    {
        D1(printk(KERN_DEBUG "Not rotating empty free_list\n"));
    }
}
